/*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
* Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
* Adapted for Power Macintosh by Paul Mackerras.
* Low-level exception handlers and MMU support
* rewritten by Paul Mackerras.
* Copyright (C) 1996 Paul Mackerras.
* MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
* Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
*
* This file contains the low-level support and setup for the
* PowerPC platform, including trap and interrupt dispatch.
* (The PPC 8xx embedded CPUs use head_8xx.S instead.)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/config.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/cputable.h>
#include <asm/cache.h>
#include <asm/thread_info.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#ifdef CONFIG_APUS
#include <asm/amigappc.h>
#endif
/* 601 only have IBAT; cr0.eq is set on 601 when using this macro */
#define LOAD_BAT(n, reg, RA, RB) \
/* see the comment for clear_bats() -- Cort */ \
li RA,0; \
mtspr SPRN_IBAT##n##U,RA; \
mtspr SPRN_DBAT##n##U,RA; \
lwz RA,(n*16)+0(reg); \
lwz RB,(n*16)+4(reg); \
mtspr SPRN_IBAT##n##U,RA; \
mtspr SPRN_IBAT##n##L,RB; \
beq 1f; \
lwz RA,(n*16)+8(reg); \
lwz RB,(n*16)+12(reg); \
mtspr SPRN_DBAT##n##U,RA; \
mtspr SPRN_DBAT##n##L,RB; \
1:
.text
.stabs "arch/ppc/kernel/",N_SO,0,0,0f
.stabs "head.S",N_SO,0,0,0f
0:
.globl _stext
_stext:
/*
* _start is defined this way because the XCOFF loader in the OpenFirmware
* on the powermac expects the entry point to be a procedure descriptor.
*/
.text
.globl _start
_start:
/*
* These are here for legacy reasons, the kernel used to
* need to look like a coff function entry for the pmac
* but we're always started by some kind of bootloader now.
* -- Cort
*/
nop /* used by __secondary_hold on prep (mtx) and chrp smp */
nop /* used by __secondary_hold on prep (mtx) and chrp smp */
nop
/* PMAC
* Enter here with the kernel text, data and bss loaded starting at
* 0, running with virtual == physical mapping.
* r5 points to the prom entry point (the client interface handler
* address). Address translation is turned on, with the prom
* managing the hash table. Interrupts are disabled. The stack
* pointer (r1) points to just below the end of the half-meg region
* from 0x380000 - 0x400000, which is mapped in already.
*
* If we are booted from MacOS via BootX, we enter with the kernel
* image loaded somewhere, and the following values in registers:
* r3: 'BooX' (0x426f6f58)
* r4: virtual address of boot_infos_t
* r5: 0
*
* APUS
* r3: 'APUS'
* r4: physical address of memory base
* Linux/m68k style BootInfo structure at &_end.
*
* PREP
* This is jumped to on prep systems right after the kernel is relocated
* to its proper place in memory by the boot loader. The expected layout
* of the regs is:
* r3: ptr to residual data
* r4: initrd_start or if no initrd then 0
* r5: initrd_end - unused if r4 is 0
* r6: Start of command line string
* r7: End of command line string
*
* This just gets a minimal mmu environment setup so we can call
* start_here() to do the real work.
* -- Cort
*/
.globl __start
__start:
mr r31,r3 /* save parameters */
mr r30,r4
mr r29,r5
mr r28,r6
mr r27,r7
li r24,0 /* cpu # */
/*
* early_init() does the early machine identification and does
* the necessary low-level setup and clears the BSS
* -- Cort <cort@fsmlabs.com>
*/
bl early_init
#ifdef CONFIG_APUS
/* On APUS the __va/__pa constants need to be set to the correct
* values before continuing.
*/
mr r4,r30
bl fix_mem_constants
#endif /* CONFIG_APUS */
/* Switch MMU off, clear BATs and flush TLB. At this point, r3 contains
* the physical address we are running at, returned by early_init()
*/
bl mmu_off
__after_mmu_off:
bl clear_bats
bl flush_tlbs
bl initial_bats
#if !defined(CONFIG_APUS) && defined(CONFIG_BOOTX_TEXT)
bl setup_disp_bat
#endif
/*
* Call setup_cpu for CPU 0 and initialize 6xx Idle
*/
bl reloc_offset
li r24,0 /* cpu# */
bl call_setup_cpu /* Call setup_cpu for this CPU */
#ifdef CONFIG_6xx
bl reloc_offset
bl init_idle_6xx
#endif /* CONFIG_6xx */
#ifndef CONFIG_APUS
/*
* We need to run with _start at physical address 0.
* If the MMU is already turned on, we copy stuff to KERNELBASE,
* otherwise we copy it to 0.
*/
bl reloc_offset
mr r26,r3
addis r4,r3,KERNELBASE@h /* current address of _start */
cmpwi 0,r4,0 /* are we already running at 0? */
bne relocate_kernel
#endif /* CONFIG_APUS */
/*
* we now have the 1st 16M of ram mapped with the bats.
* prep needs the mmu to be turned on here, but pmac already has it on.
* this shouldn't bother the pmac since it just gets turned on again
* as we jump to our code at KERNELBASE. -- Cort
* Actually no, pmac doesn't have it on any more. BootX enters with MMU
* off, and in other cases, we now turn it off before changing BATs above.
*/
turn_on_mmu:
mfmsr r0
ori r0,r0,MSR_DR|MSR_IR
mtspr SPRN_SRR1,r0
lis r0,start_here@h
ori r0,r0,start_here@l
mtspr SPRN_SRR0,r0
SYNC
RFI /* enables MMU */
/*
* We need __secondary_hold as a place to hold the other cpus on
* an SMP machine, even when we are running a UP kernel.
*/
. = 0xc0 /* for prep bootloader */
li r3,1 /* MTX only has 1 cpu */
.globl __secondary_hold
__secondary_hold:
/* tell the master we're here */
stw r3,4(0)
#ifdef CONFIG_SMP
100: lwz r4,0(0)
/* wait until we're told to start */
cmpw 0,r4,r3
bne 100b
/* our cpu # was at addr 0 - go */
mr r24,r3 /* cpu # */
b __secondary_start
#else
b .
#endif /* CONFIG_SMP */
/*
* Exception entry code. This code runs with address translation
* turned off, i.e. using physical addresses.
* We assume sprg3 has the physical address of the current
* task's thread_struct.
*/
#define EXCEPTION_PROLOG \
mtspr SPRN_SPRG0,r10; \
mtspr SPRN_SPRG1,r11; \
mfcr r10; \
EXCEPTION_PROLOG_1; \
EXCEPTION_PROLOG_2
#define EXCEPTION_PROLOG_1 \
mfspr r11,SPRN_SRR1; /* check whether user or kernel */ \
andi. r11,r11,MSR_PR; \
tophys(r11,r1); /* use tophys(r1) if kernel */ \
beq 1f; \
mfspr r11,SPRN_SPRG3; \
lwz r11,THREAD_INFO-THREAD(r11); \
addi r11,r11,THREAD_SIZE; \
tophys(r11,r11); \
1: subi r11,r11,INT_FRAME_SIZE /* alloc exc. frame */
#define EXCEPTION_PROLOG_2 \
CLR_TOP32(r11); \
stw r10,_CCR(r11); /* save registers */ \
stw r12,GPR12(r11); \
stw r9,GPR9(r11); \
mfspr r10,SPRN_SPRG0; \
stw r10,GPR10(r11); \
mfspr r12,SPRN_SPRG1; \
stw r12,GPR11(r11); \
mflr r10; \
stw r10,_LINK(r11); \
mfspr r12,SPRN_SRR0; \
mfspr r9,SPRN_SRR1; \
stw r1,GPR1(r11); \
stw r1,0(r11); \
tovirt(r1,r11); /* set new kernel sp */ \
li r10,MSR_KERNEL & ~(MSR_IR|MSR_DR); /* can take exceptions */ \
MTMSRD(r10); /* (except for mach check in rtas) */ \
stw r0,GPR0(r11); \
SAVE_4GPRS(3, r11); \
SAVE_2GPRS(7, r11)
/*
* Note: code which follows this uses cr0.eq (set if from kernel),
* r11, r12 (SRR0), and r9 (SRR1).
*
* Note2: once we have set r1 we are in a position to take exceptions
* again, and we could thus set MSR:RI at that point.
*/
/*
* Exception vectors.
*/
#define EXCEPTION(n, label, hdlr, xfer) \
. = n; \
label: \
EXCEPTION_PROLOG; \
addi r3,r1,STACK_FRAME_OVERHEAD; \
xfer(n, hdlr)
#define EXC_XFER_TEMPLATE(n, hdlr, trap, copyee, tfer, ret) \
li r10,trap; \
stw r10,TRAP(r11); \
li r10,MSR_KERNEL; \
copyee(r10, r9); \
bl tfer; \
i##n: \
.long hdlr; \
.long ret
#define COPY_EE(d, s) rlwimi d,s,0,16,16
#define NOCOPY(d, s)
#define EXC_XFER_STD(n, hdlr) \
EXC_XFER_TEMPLATE(n, hdlr, n, NOCOPY, transfer_to_handler_full, \
ret_from_except_full)
#define EXC_XFER_LITE(n, hdlr) \
EXC_XFER_TEMPLATE(n, hdlr, n+1, NOCOPY, transfer_to_handler, \
ret_from_except)
#define EXC_XFER_EE(n, hdlr) \
EXC_XFER_TEMPLATE(n, hdlr, n, COPY_EE, transfer_to_handler_full, \
ret_from_except_full)
#define EXC_XFER_EE_LITE(n, hdlr) \
EXC_XFER_TEMPLATE(n, hdlr, n+1, COPY_EE, transfer_to_handler, \
ret_from_except)
/* System reset */
/* core99 pmac starts the seconary here by changing the vector, and
putting it back to what it was (unknown_exception) when done. */
#if defined(CONFIG_GEMINI) && defined(CONFIG_SMP)
. = 0x100
b __secondary_start_gemini
#else
EXCEPTION(0x100, Reset, unknown_exception, EXC_XFER_STD)
#endif
/* Machine check */
. = 0x200
mtspr SPRN_SPRG0,r10
mtspr SPRN_SPRG1,r11
mfcr r10
EXCEPTION_PROLOG_1
7: EXCEPTION_PROLOG_2
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_STD(0x200, machine_check_exception)
/* Data access exception. */
. = 0x300
DataAccess:
EXCEPTION_PROLOG
mfspr r10,SPRN_DSISR
andis. r0,r10,0xa470 /* weird error? */
bne 1f /* if not, try to put a PTE */
mfspr r4,SPRN_DAR /* into the hash table */
rlwinm r3,r10,32-15,21,21 /* DSISR_STORE -> _PAGE_RW */
bl hash_page
1: stw r10,_DSISR(r11)
mr r5,r10
mfspr r4,SPRN_DAR
EXC_XFER_EE_LITE(0x300, handle_page_fault)
/* Instruction access exception. */
. = 0x400
InstructionAccess:
EXCEPTION_PROLOG
andis. r0,r9,0x4000 /* no pte found? */
beq 1f /* if so, try to put a PTE */
li r3,0 /* into the hash table */
mr r4,r12 /* SRR0 is fault address */
bl hash_page
1: mr r4,r12
mr r5,r9
EXC_XFER_EE_LITE(0x400, handle_page_fault)
/* External interrupt */
EXCEPTION(0x500, HardwareInterrupt, do_IRQ, EXC_XFER_LITE)
/* Alignment exception */
. = 0x600
Alignment:
EXCEPTION_PROLOG
mfspr r4,SPRN_DAR
stw r4,_DAR(r11)
mfspr r5,SPRN_DSISR
stw r5,_DSISR(r11)
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_EE(0x600, alignment_exception)
/* Program check exception */
EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD)
/* Floating-point unavailable */
. = 0x800
FPUnavailable:
EXCEPTION_PROLOG
bne load_up_fpu /* if from user, just load it up */
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_EE_LITE(0x800, kernel_fp_unavailable_exception)
/* Decrementer */
EXCEPTION(0x900, Decrementer, timer_interrupt, EXC_XFER_LITE)
EXCEPTION(0xa00, Trap_0a, unknown_exception, EXC_XFER_EE)
EXCEPTION(0xb00, Trap_0b, unknown_exception, EXC_XFER_EE)
/* System call */
. = 0xc00
SystemCall:
EXCEPTION_PROLOG
EXC_XFER_EE_LITE(0xc00, DoSyscall)
/* Single step - not used on 601 */
EXCEPTION(0xd00, SingleStep, single_step_exception, EXC_XFER_STD)
EXCEPTION(0xe00, Trap_0e, unknown_exception, EXC_XFER_EE)
/*
* The Altivec unavailable trap is at 0x0f20. Foo.
* We effectively remap it to 0x3000.
* We include an altivec unavailable exception vector even if
* not configured for Altivec, so that you can't panic a
* non-altivec kernel running on a machine with altivec just
* by executing an altivec instruction.
*/
. = 0xf00
b Trap_0f
. = 0xf20
b AltiVecUnavailable
Trap_0f:
EXCEPTION_PROLOG
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_EE(0xf00, unknown_exception)
/*
* Handle TLB miss for instruction on 603/603e.
* Note: we get an alternate set of r0 - r3 to use automatically.
*/
. = 0x1000
InstructionTLBMiss:
/*
* r0: stored ctr
* r1: linux style pte ( later becomes ppc hardware pte )
* r2: ptr to linux-style pte
* r3: scratch
*/
mfctr r0
/* Get PTE (linux-style) and check access */
mfspr r3,SPRN_IMISS
lis r1,KERNELBASE@h /* check if kernel address */
cmplw 0,r3,r1
mfspr r2,SPRN_SPRG3
li r1,_PAGE_USER|_PAGE_PRESENT /* low addresses tested as user */
lwz r2,PGDIR(r2)
blt+ 112f
lis r2,swapper_pg_dir@ha /* if kernel address, use */
addi r2,r2,swapper_pg_dir@l /* kernel page table */
mfspr r1,SPRN_SRR1 /* and MSR_PR bit from SRR1 */
rlwinm r1,r1,32-12,29,29 /* shift MSR_PR to _PAGE_USER posn */
112: tophys(r2,r2)
rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
lwz r2,0(r2) /* get pmd entry */
rlwinm. r2,r2,0,0,19 /* extract address of pte page */
beq- InstructionAddressInvalid /* return if no mapping */
rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */
lwz r3,0(r2) /* get linux-style pte */
andc. r1,r1,r3 /* check access & ~permission */
bne- InstructionAddressInvalid /* return if access not permitted */
ori r3,r3,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */
/*
* NOTE! We are assuming this is not an SMP system, otherwise
* we would need to update the pte atomically with lwarx/stwcx.
*/
stw r3,0(r2) /* update PTE (accessed bit) */
/* Convert linux-style PTE to low word of PPC-style PTE */
rlwinm r1,r3,32-10,31,31 /* _PAGE_RW -> PP lsb */
rlwinm r2,r3,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */
and r1,r1,r2 /* writable if _RW and _DIRTY */
rlwimi r3,r3,32-1,30,30 /* _PAGE_USER -> PP msb */
rlwimi r3,r3,32-1,31,31 /* _PAGE_USER -> PP lsb */
ori r1,r1,0xe14 /* clear out reserved bits and M */
andc r1,r3,r1 /* PP = user? (rw&dirty? 2: 3): 0 */
mtspr SPRN_RPA,r1
mfspr r3,SPRN_IMISS
tlbli r3
mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r3
rfi
InstructionAddressInvalid:
mfspr r3,SPRN_SRR1
rlwinm r1,r3,9,6,6 /* Get load/store bit */
addis r1,r1,0x2000
mtspr SPRN_DSISR,r1 /* (shouldn't be needed) */
mtctr r0 /* Restore CTR */
andi. r2,r3,0xFFFF /* Clear upper bits of SRR1 */
or r2,r2,r1
mtspr SPRN_SRR1,r2
mfspr r1,SPRN_IMISS /* Get failing address */
rlwinm. r2,r2,0,31,31 /* Check for little endian access */
rlwimi r2,r2,1,30,30 /* change 1 -> 3 */
xor r1,r1,r2
mtspr SPRN_DAR,r1 /* Set fault address */
mfmsr r0 /* Restore "normal" registers */
xoris r0,r0,MSR_TGPR>>16
mtcrf 0x80,r3 /* Restore CR0 */
mtmsr r0
b InstructionAccess
/*
* Handle TLB miss for DATA Load operation on 603/603e
*/
. = 0x1100
DataLoadTLBMiss:
/*
* r0: stored ctr
* r1: linux style pte ( later becomes ppc hardware pte )
* r2: ptr to linux-style pte
* r3: scratch
*/
mfctr r0
/* Get PTE (linux-style) and check access */
mfspr r3,SPRN_DMISS
lis r1,KERNELBASE@h /* check if kernel address */
cmplw 0,r3,r1
mfspr r2,SPRN_SPRG3
li r1,_PAGE_USER|_PAGE_PRESENT /* low addresses tested as user */
lwz r2,PGDIR(r2)
blt+ 112f
lis r2,swapper_pg_dir@ha /* if kernel address, use */
addi r2,r2,swapper_pg_dir@l /* kernel page table */
mfspr r1,SPRN_SRR1 /* and MSR_PR bit from SRR1 */
rlwinm r1,r1,32-12,29,29 /* shift MSR_PR to _PAGE_USER posn */
112: tophys(r2,r2)
rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
lwz r2,0(r2) /* get pmd entry */
rlwinm. r2,r2,0,0,19 /* extract address of pte page */
beq- DataAddressInvalid /* return if no mapping */
rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */
lwz r3,0(r2) /* get linux-style pte */
andc. r1,r1,r3 /* check access & ~permission */
bne- DataAddressInvalid /* return if access not permitted */
ori r3,r3,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */
/*
* NOTE! We are assuming this is not an SMP system, otherwise
* we would need to update the pte atomically with lwarx/stwcx.
*/
stw r3,0(r2) /* update PTE (accessed bit) */
/* Convert linux-style PTE to low word of PPC-style PTE */
rlwinm r1,r3,32-10,31,31 /* _PAGE_RW -> PP lsb */
rlwinm r2,r3,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */
and r1,r1,r2 /* writable if _RW and _DIRTY */
rlwimi r3,r3,32-1,30,30 /* _PAGE_USER -> PP msb */
rlwimi r3,r3,32-1,31,31 /* _PAGE_USER -> PP lsb */
ori r1,r1,0xe14 /* clear out reserved bits and M */
andc r1,r3,r1 /* PP = user? (rw&dirty? 2: 3): 0 */
mtspr SPRN_RPA,r1
mfspr r3,SPRN_DMISS
tlbld r3
mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r3
rfi
DataAddressInvalid:
mfspr r3,SPRN_SRR1
rlwinm r1,r3,9,6,6 /* Get load/store bit */
addis r1,r1,0x2000
mtspr SPRN_DSISR,r1
mtctr r0 /* Restore CTR */
andi. r2,r3,0xFFFF /* Clear upper bits of SRR1 */
mtspr SPRN_SRR1,r2
mfspr r1,SPRN_DMISS /* Get failing address */
rlwinm. r2,r2,0,31,31 /* Check for little endian access */
beq 20f /* Jump if big endian */
xori r1,r1,3
20: mtspr SPRN_DAR,r1 /* Set fault address */
mfmsr r0 /* Restore "normal" registers */
xoris r0,r0,MSR_TGPR>>16
mtcrf 0x80,r3 /* Restore CR0 */
mtmsr r0
b DataAccess
/*
* Handle TLB miss for DATA Store on 603/603e
*/
. = 0x1200
DataStoreTLBMiss:
/*
* r0: stored ctr
* r1: linux style pte ( later becomes ppc hardware pte )
* r2: ptr to linux-style pte
* r3: scratch
*/
mfctr r0
/* Get PTE (linux-style) and check access */
mfspr r3,SPRN_DMISS
lis r1,KERNELBASE@h /* check if kernel address */
cmplw 0,r3,r1
mfspr r2,SPRN_SPRG3
li r1,_PAGE_RW|_PAGE_USER|_PAGE_PRESENT /* access flags */
lwz r2,PGDIR(r2)
blt+ 112f
lis r2,swapper_pg_dir@ha /* if kernel address, use */
addi r2,r2,swapper_pg_dir@l /* kernel page table */
mfspr r1,SPRN_SRR1 /* and MSR_PR bit from SRR1 */
rlwinm r1,r1,32-12,29,29 /* shift MSR_PR to _PAGE_USER posn */
112: tophys(r2,r2)
rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
lwz r2,0(r2) /* get pmd entry */
rlwinm. r2,r2,0,0,19 /* extract address of pte page */
beq- DataAddressInvalid /* return if no mapping */
rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */
lwz r3,0(r2) /* get linux-style pte */
andc. r1,r1,r3 /* check access & ~permission */
bne- DataAddressInvalid /* return if access not permitted */
ori r3,r3,_PAGE_ACCESSED|_PAGE_DIRTY
/*
* NOTE! We are assuming this is not an SMP system, otherwise
* we would need to update the pte atomically with lwarx/stwcx.
*/
stw r3,0(r2) /* update PTE (accessed/dirty bits) */
/* Convert linux-style PTE to low word of PPC-style PTE */
rlwimi r3,r3,32-1,30,30 /* _PAGE_USER -> PP msb */
li r1,0xe15 /* clear out reserved bits and M */
andc r1,r3,r1 /* PP = user? 2: 0 */
mtspr SPRN_RPA,r1
mfspr r3,SPRN_DMISS
tlbld r3
mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r3
rfi
#ifndef CONFIG_ALTIVEC
#define altivec_assist_exception unknown_exception
#endif
EXCEPTION(0x1300, Trap_13, instruction_breakpoint_exception, EXC_XFER_EE)
EXCEPTION(0x1400, SMI, SMIException, EXC_XFER_EE)
EXCEPTION(0x1500, Trap_15, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1600, Trap_16, altivec_assist_exception, EXC_XFER_EE)
EXCEPTION(0x1700, Trap_17, TAUException, EXC_XFER_STD)
EXCEPTION(0x1800, Trap_18, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1900, Trap_19, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1a00, Trap_1a, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1b00, Trap_1b, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1c00, Trap_1c, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1d00, Trap_1d, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1e00, Trap_1e, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1f00, Trap_1f, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2000, RunMode, RunModeException, EXC_XFER_EE)
EXCEPTION(0x2100, Trap_21, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2200, Trap_22, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2300, Trap_23, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2400, Trap_24, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2500, Trap_25, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2600, Trap_26, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2700, Trap_27, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2800, Trap_28, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2900, Trap_29, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2a00, Trap_2a, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2b00, Trap_2b, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2c00, Trap_2c, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2d00, Trap_2d, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2e00, Trap_2e, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2f00, MOLTrampoline, unknown_exception, EXC_XFER_EE_LITE)
.globl mol_trampoline
.set mol_trampoline, i0x2f00
. = 0x3000
AltiVecUnavailable:
EXCEPTION_PROLOG
#ifdef CONFIG_ALTIVEC
bne load_up_altivec /* if from user, just load it up */
#endif /* CONFIG_ALTIVEC */
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_EE_LITE(0xf20, altivec_unavailable_exception)
#ifdef CONFIG_ALTIVEC
/* Note that the AltiVec support is closely modeled after the FP
* support. Changes to one are likely to be applicable to the
* other! */
load_up_altivec:
/*
* Disable AltiVec for the task which had AltiVec previously,
* and save its AltiVec registers in its thread_struct.
* Enables AltiVec for use in the kernel on return.
* On SMP we know the AltiVec units are free, since we give it up every
* switch. -- Kumar
*/
mfmsr r5
oris r5,r5,MSR_VEC@h
MTMSRD(r5) /* enable use of AltiVec now */
isync
/*
* For SMP, we don't do lazy AltiVec switching because it just gets too
* horrendously complex, especially when a task switches from one CPU
* to another. Instead we call giveup_altivec in switch_to.
*/
#ifndef CONFIG_SMP
tophys(r6,0)
addis r3,r6,last_task_used_altivec@ha
lwz r4,last_task_used_altivec@l(r3)
cmpwi 0,r4,0
beq 1f
add r4,r4,r6
addi r4,r4,THREAD /* want THREAD of last_task_used_altivec */
SAVE_32VRS(0,r10,r4)
mfvscr vr0
li r10,THREAD_VSCR
stvx vr0,r10,r4
lwz r5,PT_REGS(r4)
add r5,r5,r6
lwz r4,_MSR-STACK_FRAME_OVERHEAD(r5)
lis r10,MSR_VEC@h
andc r4,r4,r10 /* disable altivec for previous task */
stw r4,_MSR-STACK_FRAME_OVERHEAD(r5)
1:
#endif /* CONFIG_SMP */
/* enable use of AltiVec after return */
oris r9,r9,MSR_VEC@h
mfspr r5,SPRN_SPRG3 /* current task's THREAD (phys) */
li r4,1
li r10,THREAD_VSCR
stw r4,THREAD_USED_VR(r5)
lvx vr0,r10,r5
mtvscr vr0
REST_32VRS(0,r10,r5)
#ifndef CONFIG_SMP
subi r4,r5,THREAD
sub r4,r4,r6
stw r4,last_task_used_altivec@l(r3)
#endif /* CONFIG_SMP */
/* restore registers and return */
/* we haven't used ctr or xer or lr */
b fast_exception_return
/*
* AltiVec unavailable trap from kernel - print a message, but let
* the task use AltiVec in the kernel until it returns to user mode.
*/
KernelAltiVec:
lwz r3,_MSR(r1)
oris r3,r3,MSR_VEC@h
stw r3,_MSR(r1) /* enable use of AltiVec after return */
lis r3,87f@h
ori r3,r3,87f@l
mr r4,r2 /* current */
lwz r5,_NIP(r1)
bl printk
b ret_from_except
87: .string "AltiVec used in kernel (task=%p, pc=%x) \n"
.align 4,0
/*
* giveup_altivec(tsk)
* Disable AltiVec for the task given as the argument,
* and save the AltiVec registers in its thread_struct.
* Enables AltiVec for use in the kernel on return.
*/
.globl giveup_altivec
giveup_altivec:
mfmsr r5
oris r5,r5,MSR_VEC@h
SYNC
MTMSRD(r5) /* enable use of AltiVec now */
isync
cmpwi 0,r3,0
beqlr- /* if no previous owner, done */
addi r3,r3,THREAD /* want THREAD of task */
lwz r5,PT_REGS(r3)
cmpwi 0,r5,0
SAVE_32VRS(0, r4, r3)
mfvscr vr0
li r4,THREAD_VSCR
stvx vr0,r4,r3
beq 1f
lwz r4,_MSR-STACK_FRAME_OVERHEAD(r5)
lis r3,MSR_VEC@h
andc r4,r4,r3 /* disable AltiVec for previous task */
stw r4,_MSR-STACK_FRAME_OVERHEAD(r5)
1:
#ifndef CONFIG_SMP
li r5,0
lis r4,last_task_used_altivec@ha
stw r5,last_task_used_altivec@l(r4)
#endif /* CONFIG_SMP */
blr
#endif /* CONFIG_ALTIVEC */
/*
* This code is jumped to from the startup code to copy
* the kernel image to physical address 0.
*/
relocate_kernel:
addis r9,r26,klimit@ha /* fetch klimit */
lwz r25,klimit@l(r9)
addis r25,r25,-KERNELBASE@h
li r3,0 /* Destination base address */
li r6,0 /* Destination offset */
li r5,0x4000 /* # bytes of memory to copy */
bl copy_and_flush /* copy the first 0x4000 bytes */
addi r0,r3,4f@l /* jump to the address of 4f */
mtctr r0 /* in copy and do the rest. */
bctr /* jump to the copy */
4: mr r5,r25
bl copy_and_flush /* copy the rest */
b turn_on_mmu
/*
* Copy routine used to copy the kernel to start at physical address 0
* and flush and invalidate the caches as needed.
* r3 = dest addr, r4 = source addr, r5 = copy limit, r6 = start offset
* on exit, r3, r4, r5 are unchanged, r6 is updated to be >= r5.
*/
copy_and_flush:
addi r5,r5,-4
addi r6,r6,-4
4: li r0,L1_CACHE_BYTES/4
mtctr r0
3: addi r6,r6,4 /* copy a cache line */
lwzx r0,r6,r4
stwx r0,r6,r3
bdnz 3b
dcbst r6,r3 /* write it to memory */
sync
icbi r6,r3 /* flush the icache line */
cmplw 0,r6,r5
blt 4b
sync /* additional sync needed on g4 */
isync
addi r5,r5,4
addi r6,r6,4
blr
#ifdef CONFIG_APUS
/*
* On APUS the physical base address of the kernel is not known at compile
* time, which means the __pa/__va constants used are incorrect. In the
* __init section is recorded the virtual addresses of instructions using
* these constants, so all that has to be done is fix these before
* continuing the kernel boot.
*
* r4 = The physical address of the kernel base.
*/
fix_mem_constants:
mr r10,r4
addis r10,r10,-KERNELBASE@h /* virt_to_phys constant */
neg r11,r10 /* phys_to_virt constant */
lis r12,__vtop_table_begin@h
ori r12,r12,__vtop_table_begin@l
add r12,r12,r10 /* table begin phys address */
lis r13,__vtop_table_end@h
ori r13,r13,__vtop_table_end@l
add r13,r13,r10 /* table end phys address */
subi r12,r12,4
subi r13,r13,4
1: lwzu r14,4(r12) /* virt address of instruction */
add r14,r14,r10 /* phys address of instruction */
lwz r15,0(r14) /* instruction, now insert top */
rlwimi r15,r10,16,16,31 /* half of vp const in low half */
stw r15,0(r14) /* of instruction and restore. */
dcbst r0,r14 /* write it to memory */
sync
icbi r0,r14 /* flush the icache line */
cmpw r12,r13
bne 1b
sync /* additional sync needed on g4 */
isync
/*
* Map the memory where the exception handlers will
* be copied to when hash constants have been patched.
*/
#ifdef CONFIG_APUS_FAST_EXCEPT
lis r8,0xfff0
#else
lis r8,0
#endif
ori r8,r8,0x2 /* 128KB, supervisor */
mtspr SPRN_DBAT3U,r8
mtspr SPRN_DBAT3L,r8
lis r12,__ptov_table_begin@h
ori r12,r12,__ptov_table_begin@l
add r12,r12,r10 /* table begin phys address */
lis r13,__ptov_table_end@h
ori r13,r13,__ptov_table_end@l
add r13,r13,r10 /* table end phys address */
subi r12,r12,4
subi r13,r13,4
1: lwzu r14,4(r12) /* virt address of instruction */
add r14,r14,r10 /* phys address of instruction */
lwz r15,0(r14) /* instruction, now insert top */
rlwimi r15,r11,16,16,31 /* half of pv const in low half*/
stw r15,0(r14) /* of instruction and restore. */
dcbst r0,r14 /* write it to memory */
sync
icbi r0,r14 /* flush the icache line */
cmpw r12,r13
bne 1b
sync /* additional sync needed on g4 */
isync /* No speculative loading until now */
blr
/***********************************************************************
* Please note that on APUS the exception handlers are located at the
* physical address 0xfff0000. For this reason, the exception handlers
* cannot use relative branches to access the code below.
***********************************************************************/
#endif /* CONFIG_APUS */
#ifdef CONFIG_SMP
#ifdef CONFIG_GEMINI
.globl __secondary_start_gemini
__secondary_start_gemini:
mfspr r4,SPRN_HID0
ori r4,r4,HID0_ICFI
li r3,0
ori r3,r3,HID0_ICE
andc r4,r4,r3
mtspr SPRN_HID0,r4
sync
b __secondary_start
#endif /* CONFIG_GEMINI */
.globl __secondary_start_pmac_0
__secondary_start_pmac_0:
/* NB the entries for cpus 0, 1, 2 must each occupy 8 bytes. */
li r24,0
b 1f
li r24,1
b 1f
li r24,2
b 1f
li r24,3
1:
/* on powersurge, we come in here with IR=0 and DR=1, and DBAT 0
set to map the 0xf0000000 - 0xffffffff region */
mfmsr r0
rlwinm r0,r0,0,28,26 /* clear DR (0x10) */
SYNC
mtmsr r0
isync
.globl __secondary_start
__secondary_start:
/* Copy some CPU settings from CPU 0 */
bl __restore_cpu_setup
lis r3,-KERNELBASE@h
mr r4,r24
bl call_setup_cpu /* Call setup_cpu for this CPU */
#ifdef CONFIG_6xx
lis r3,-KERNELBASE@h
bl init_idle_6xx
#endif /* CONFIG_6xx */
/* get current_thread_info and current */
lis r1,secondary_ti@ha
tophys(r1,r1)
lwz r1,secondary_ti@l(r1)
tophys(r2,r1)
lwz r2,TI_TASK(r2)
/* stack */
addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
li r0,0
tophys(r3,r1)
stw r0,0(r3)
/* load up the MMU */
bl load_up_mmu
/* ptr to phys current thread */
tophys(r4,r2)
addi r4,r4,THREAD /* phys address of our thread_struct */
CLR_TOP32(r4)
mtspr SPRN_SPRG3,r4
li r3,0
mtspr SPRN_SPRG2,r3 /* 0 => not in RTAS */
/* enable MMU and jump to start_secondary */
li r4,MSR_KERNEL
FIX_SRR1(r4,r5)
lis r3,start_secondary@h
ori r3,r3,start_secondary@l
mtspr SPRN_SRR0,r3
mtspr SPRN_SRR1,r4
SYNC
RFI
#endif /* CONFIG_SMP */
/*
* Those generic dummy functions are kept for CPUs not
* included in CONFIG_6xx
*/
#if !defined(CONFIG_6xx)
_GLOBAL(__save_cpu_setup)
blr
_GLOBAL(__restore_cpu_setup)
blr
#endif /* !defined(CONFIG_6xx) */
/*
* Load stuff into the MMU. Intended to be called with
* IR=0 and DR=0.
*/
load_up_mmu:
sync /* Force all PTE updates to finish */
isync
tlbia /* Clear all TLB entries */
sync /* wait for tlbia/tlbie to finish */
TLBSYNC /* ... on all CPUs */
/* Load the SDR1 register (hash table base & size) */
lis r6,_SDR1@ha
tophys(r6,r6)
lwz r6,_SDR1@l(r6)
mtspr SPRN_SDR1,r6
li r0,16 /* load up segment register values */
mtctr r0 /* for context 0 */
lis r3,0x2000 /* Ku = 1, VSID = 0 */
li r4,0
3: mtsrin r3,r4
addi r3,r3,0x111 /* increment VSID */
addis r4,r4,0x1000 /* address of next segment */
bdnz 3b
/* Load the BAT registers with the values set up by MMU_init.
MMU_init takes care of whether we're on a 601 or not. */
mfpvr r3
srwi r3,r3,16
cmpwi r3,1
lis r3,BATS@ha
addi r3,r3,BATS@l
tophys(r3,r3)
LOAD_BAT(0,r3,r4,r5)
LOAD_BAT(1,r3,r4,r5)
LOAD_BAT(2,r3,r4,r5)
LOAD_BAT(3,r3,r4,r5)
blr
/*
* This is where the main kernel code starts.
*/
start_here:
/* ptr to current */
lis r2,init_task@h
ori r2,r2,init_task@l
/* Set up for using our exception vectors */
/* ptr to phys current thread */
tophys(r4,r2)
addi r4,r4,THREAD /* init task's THREAD */
CLR_TOP32(r4)
mtspr SPRN_SPRG3,r4
li r3,0
mtspr SPRN_SPRG2,r3 /* 0 => not in RTAS */
/* stack */
lis r1,init_thread_union@ha
addi r1,r1,init_thread_union@l
li r0,0
stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)
/*
* Do early bootinfo parsing, platform-specific initialization,
* and set up the MMU.
*/
mr r3,r31
mr r4,r30
mr r5,r29
mr r6,r28
mr r7,r27
bl machine_init
bl MMU_init
#ifdef CONFIG_APUS
/* Copy exception code to exception vector base on APUS. */
lis r4,KERNELBASE@h
#ifdef CONFIG_APUS_FAST_EXCEPT
lis r3,0xfff0 /* Copy to 0xfff00000 */
#else
lis r3,0 /* Copy to 0x00000000 */
#endif
li r5,0x4000 /* # bytes of memory to copy */
li r6,0
bl copy_and_flush /* copy the first 0x4000 bytes */
#endif /* CONFIG_APUS */
/*
* Go back to running unmapped so we can load up new values
* for SDR1 (hash table pointer) and the segment registers
* and change to using our exception vectors.
*/
lis r4,2f@h
ori r4,r4,2f@l
tophys(r4,r4)
li r3,MSR_KERNEL & ~(MSR_IR|MSR_DR)
FIX_SRR1(r3,r5)
mtspr SPRN_SRR0,r4
mtspr SPRN_SRR1,r3
SYNC
RFI
/* Load up the kernel context */
2: bl load_up_mmu
#ifdef CONFIG_BDI_SWITCH
/* Add helper information for the Abatron bdiGDB debugger.
* We do this here because we know the mmu is disabled, and
* will be enabled for real in just a few instructions.
*/
lis r5, abatron_pteptrs@h
ori r5, r5, abatron_pteptrs@l
stw r5, 0xf0(r0) /* This much match your Abatron config */
lis r6, swapper_pg_dir@h
ori r6, r6, swapper_pg_dir@l
tophys(r5, r5)
stw r6, 0(r5)
#endif /* CONFIG_BDI_SWITCH */
/* Now turn on the MMU for real! */
li r4,MSR_KERNEL
FIX_SRR1(r4,r5)
lis r3,start_kernel@h
ori r3,r3,start_kernel@l
mtspr SPRN_SRR0,r3
mtspr SPRN_SRR1,r4
SYNC
RFI
/*
* Set up the segment registers for a new context.
*/
_GLOBAL(set_context)
mulli r3,r3,897 /* multiply context by skew factor */
rlwinm r3,r3,4,8,27 /* VSID = (context & 0xfffff) << 4 */
addis r3,r3,0x6000 /* Set Ks, Ku bits */
li r0,NUM_USER_SEGMENTS
mtctr r0
#ifdef CONFIG_BDI_SWITCH
/* Context switch the PTE pointer for the Abatron BDI2000.
* The PGDIR is passed as second argument.
*/
lis r5, KERNELBASE@h
lwz r5, 0xf0(r5)
stw r4, 0x4(r5)
#endif
li r4,0
isync
3:
mtsrin r3,r4
addi r3,r3,0x111 /* next VSID */
rlwinm r3,r3,0,8,3 /* clear out any overflow from VSID field */
addis r4,r4,0x1000 /* address of next segment */
bdnz 3b
sync
isync
blr
/*
* An undocumented "feature" of 604e requires that the v bit
* be cleared before changing BAT values.
*
* Also, newer IBM firmware does not clear bat3 and 4 so
* this makes sure it's done.
* -- Cort
*/
clear_bats:
li r10,0
mfspr r9,SPRN_PVR
rlwinm r9,r9,16,16,31 /* r9 = 1 for 601, 4 for 604 */
cmpwi r9, 1
beq 1f
mtspr SPRN_DBAT0U,r10
mtspr SPRN_DBAT0L,r10
mtspr SPRN_DBAT1U,r10
mtspr SPRN_DBAT1L,r10
mtspr SPRN_DBAT2U,r10
mtspr SPRN_DBAT2L,r10
mtspr SPRN_DBAT3U,r10
mtspr SPRN_DBAT3L,r10
1:
mtspr SPRN_IBAT0U,r10
mtspr SPRN_IBAT0L,r10
mtspr SPRN_IBAT1U,r10
mtspr SPRN_IBAT1L,r10
mtspr SPRN_IBAT2U,r10
mtspr SPRN_IBAT2L,r10
mtspr SPRN_IBAT3U,r10
mtspr SPRN_IBAT3L,r10
BEGIN_FTR_SECTION
/* Here's a tweak: at this point, CPU setup have
* not been called yet, so HIGH_BAT_EN may not be
* set in HID0 for the 745x processors. However, it
* seems that doesn't affect our ability to actually
* write to these SPRs.
*/
mtspr SPRN_DBAT4U,r10
mtspr SPRN_DBAT4L,r10
mtspr SPRN_DBAT5U,r10
mtspr SPRN_DBAT5L,r10
mtspr SPRN_DBAT6U,r10
mtspr SPRN_DBAT6L,r10
mtspr SPRN_DBAT7U,r10
mtspr SPRN_DBAT7L,r10
mtspr SPRN_IBAT4U,r10
mtspr SPRN_IBAT4L,r10
mtspr SPRN_IBAT5U,r10
mtspr SPRN_IBAT5L,r10
mtspr SPRN_IBAT6U,r10
mtspr SPRN_IBAT6L,r10
mtspr SPRN_IBAT7U,r10
mtspr SPRN_IBAT7L,r10
END_FTR_SECTION_IFSET(CPU_FTR_HAS_HIGH_BATS)
blr
flush_tlbs:
lis r10, 0x40
1: addic. r10, r10, -0x1000
tlbie r10
blt 1b
sync
blr
mmu_off:
addi r4, r3, __after_mmu_off - _start
mfmsr r3
andi. r0,r3,MSR_DR|MSR_IR /* MMU enabled? */
beqlr
andc r3,r3,r0
mtspr SPRN_SRR0,r4
mtspr SPRN_SRR1,r3
sync
RFI
/*
* Use the first pair of BAT registers to map the 1st 16MB
* of RAM to KERNELBASE. From this point on we can't safely
* call OF any more.
*/
initial_bats:
lis r11,KERNELBASE@h
mfspr r9,SPRN_PVR
rlwinm r9,r9,16,16,31 /* r9 = 1 for 601, 4 for 604 */
cmpwi 0,r9,1
bne 4f
ori r11,r11,4 /* set up BAT registers for 601 */
li r8,0x7f /* valid, block length = 8MB */
oris r9,r11,0x800000@h /* set up BAT reg for 2nd 8M */
oris r10,r8,0x800000@h /* set up BAT reg for 2nd 8M */
mtspr SPRN_IBAT0U,r11 /* N.B. 601 has valid bit in */
mtspr SPRN_IBAT0L,r8 /* lower BAT register */
mtspr SPRN_IBAT1U,r9
mtspr SPRN_IBAT1L,r10
isync
blr
4: tophys(r8,r11)
#ifdef CONFIG_SMP
ori r8,r8,0x12 /* R/W access, M=1 */
#else
ori r8,r8,2 /* R/W access */
#endif /* CONFIG_SMP */
#ifdef CONFIG_APUS
ori r11,r11,BL_8M<<2|0x2 /* set up 8MB BAT registers for 604 */
#else
ori r11,r11,BL_256M<<2|0x2 /* set up BAT registers for 604 */
#endif /* CONFIG_APUS */
mtspr SPRN_DBAT0L,r8 /* N.B. 6xx (not 601) have valid */
mtspr SPRN_DBAT0U,r11 /* bit in upper BAT register */
mtspr SPRN_IBAT0L,r8
mtspr SPRN_IBAT0U,r11
isync
blr
#if !defined(CONFIG_APUS) && defined(CONFIG_BOOTX_TEXT)
setup_disp_bat:
/*
* setup the display bat prepared for us in prom.c
*/
mflr r8
bl reloc_offset
mtlr r8
addis r8,r3,disp_BAT@ha
addi r8,r8,disp_BAT@l
lwz r11,0(r8)
lwz r8,4(r8)
mfspr r9,SPRN_PVR
rlwinm r9,r9,16,16,31 /* r9 = 1 for 601, 4 for 604 */
cmpwi 0,r9,1
beq 1f
mtspr SPRN_DBAT3L,r8
mtspr SPRN_DBAT3U,r11
blr
1: mtspr SPRN_IBAT3L,r8
mtspr SPRN_IBAT3U,r11
blr
#endif /* !defined(CONFIG_APUS) && defined(CONFIG_BOOTX_TEXT) */
#ifdef CONFIG_8260
/* Jump into the system reset for the rom.
* We first disable the MMU, and then jump to the ROM reset address.
*
* r3 is the board info structure, r4 is the location for starting.
* I use this for building a small kernel that can load other kernels,
* rather than trying to write or rely on a rom monitor that can tftp load.
*/
.globl m8260_gorom
m8260_gorom:
mfmsr r0
rlwinm r0,r0,0,17,15 /* clear MSR_EE in r0 */
sync
mtmsr r0
sync
mfspr r11, SPRN_HID0
lis r10, 0
ori r10,r10,HID0_ICE|HID0_DCE
andc r11, r11, r10
mtspr SPRN_HID0, r11
isync
li r5, MSR_ME|MSR_RI
lis r6,2f@h
addis r6,r6,-KERNELBASE@h
ori r6,r6,2f@l
mtspr SPRN_SRR0,r6
mtspr SPRN_SRR1,r5
isync
sync
rfi
2:
mtlr r4
blr
#endif
/*
* We put a few things here that have to be page-aligned.
* This stuff goes at the beginning of the data segment,
* which is page-aligned.
*/
.data
.globl sdata
sdata:
.globl empty_zero_page
empty_zero_page:
.space 4096
.globl swapper_pg_dir
swapper_pg_dir:
.space 4096
/*
* This space gets a copy of optional info passed to us by the bootstrap
* Used to pass parameters into the kernel like root=/dev/sda1, etc.
*/
.globl cmd_line
cmd_line:
.space 512
.globl intercept_table
intercept_table:
.long 0, 0, i0x200, i0x300, i0x400, 0, i0x600, i0x700
.long i0x800, 0, 0, 0, 0, i0xd00, 0, 0
.long 0, 0, 0, i0x1300, 0, 0, 0, 0
.long 0, 0, 0, 0, 0, 0, 0, 0
.long 0, 0, 0, 0, 0, 0, 0, 0
.long 0, 0, 0, 0, 0, 0, 0, 0
/* Room for two PTE pointers, usually the kernel and current user pointers
* to their respective root page table.
*/
abatron_pteptrs:
.space 8
